Method for forming diffusion regions in a silicon substrate

ABSTRACT

A method of manufacturing solar cells is disclosed. The method comprises depositing an etch-resistant dopant material on a silicon substrate, the etch-resistant dopant material comprising a dopant source, forming a cross-linked matrix in the etch-resistant dopant material using a non-thermal cure of the etch-resistant dopant material, and heating the silicon substrate and the etch-resistant dopant material to a temperature sufficient to cause the dopant source to diffuse into the silicon substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/250,594, filed on Sep. 30, 2011, the entire contents of which arehereby incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The United States government has a paid-up license in this invention andthe right in limited circumstances to require the patent owner tolicense others on reasonable terms as provided by the terms ofDE-FC36-07GO17043 awarded by the DOE.

TECHNICAL FIELD

Embodiments of the subject matter described herein relate generally tosolar cell manufacture. More particularly, embodiments of the subjectmatter relate to thin silicon solar cells and techniques formanufacture.

BACKGROUND

Solar cells are well known devices for converting solar radiation toelectrical energy. They may be fabricated on a semiconductor wafer usingsemiconductor processing technology. A solar cell includes P-type andN-type diffusion regions. Solar radiation impinging on the solar cellcreates electrons and holes that migrate to the diffusion regions,thereby creating voltage differentials between the diffusion regions. Ina backside contact solar cell, both the diffusion regions and the metalcontact fingers coupled to them are on the backside of the solar cell.The contact fingers allow an external electrical circuit to be coupledto and be powered by the solar cell.

Accordingly, techniques for improving the fabrication process andreducing the cost of manufacturing solar cells are generally desirable.Such techniques include printing and curing of dopants on siliconsubstrates through processes like ink-jet printing. These or othersimilar embodiments form the background of the current invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the subject matter may be derived byreferring to the detailed description and claims when considered inconjunction with the following figures, wherein like reference numbersrefer to similar elements throughout the figures.

FIGS. 1-9 are cross-sectional representations of a solar cell beingfabricated in accordance with an embodiment of the invention

FIGS. 10-17 are cross-sectional representations of a solar cell beingfabricated in accordance with another embodiment of the invention

FIGS. 18-31 are cross-sectional representations of a solar cell beingfabricated in accordance with yet another embodiment of the invention

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,brief summary or the following detailed description.

One technique for simplifying formation of doped diffusion regions in asilicon substrate during the photovoltaic solar cell manufacturingprocess is using printed dopant paste, including ink-jet dispenseddopants, on a silicon substrate. The printed dopant paste can be thenheated to drive dopant material into the underlying silicon to create adoped diffusion region in the silicon substrate, a step in creating aphotovoltaic solar cell. Certain printed dopant pastes can becomethermally unstable, resulting in outgassing of dopant material from thedopant paste into the ambient environment. This, in turn, can causecounterdoping, where the outgassed dopant in the ambient environment mayre-deposit in undesired areas of the silicon substrate. This thermalinstability can manifest during any post-print heating process,including bake and dopant driving processes, when the temperature of theenvironment is being raised. It should be noted that any reference to adopant paste refers to a suspension or solution of any type whichincludes doping materials. The substance need not be a paste, but can bea liquid, solution, suspension, solid, semi-solid, or any other physicalstate.

An improvement to the process can be to perform a non-thermal cureprocess to form a cross-linked matrix in the dopant paste prior to thethermal dopant driving step. In one embodiment, for example, thisprocess can reduce the thermal-driven mass-loss phenomena or outgassingduring the heating for dopant driving by photo-polymerization orphoto-curing of the dopant paste.

A method of manufacturing solar cells is disclosed. The method comprisesdepositing an etch-resistant dopant material on a silicon substrate, theetch-resistant dopant material comprising a dopant source, forming across-linked matrix in the etch-resistant dopant material using anon-thermal cure of the etch-resistant dopant material, and heating thesilicon substrate and the etch-resistant dopant material to atemperature sufficient to cause the dopant source to diffuse into thesilicon substrate.

Another method of manufacturing solar cells is disclosed. The methodcomprises depositing a dopant material on a silicon substrate having aphotovoltaic solar cell structure, forming a cross-linked matrix in thedopant material using a non-thermal exposure of the etch-resistantdopant material to ultraviolet light through a photo-polymerizationprocess, and heating the silicon substrate of the dopant material to atemperature sufficient to cause the dopant source to diffuse into thesilicon substrate.

Yet another method of manufacturing solar cells is disclosed. The methodcomprises forming a thin dielectric layer on a surface of a siliconsubstrate, forming a polysilicon layer over the thin dielectric layer,depositing an etch-resistant dopant material comprising a dopant sourcematerial on the polysilicon layer, forming a cross-linked matrix in theetch-resistant dopant material using a non-thermal cure of theetch-resistant dopant material, heating the etch-resistant dopantmaterial to a temperature wherein the dopant source material diffusesinto the polysilicon layer, and selectively etching to remove the dopantsource material without etching the polysilicon layer.

The various tasks performed in connection with the manufacturing processshown in FIGS. 2-6 may include any number of additional or alternativetasks such as FIGS. 7-9. The manufacturing process shown in FIGS. 10-17and FIGS. 18-31 need not be performed in the illustrated order, and itmay be incorporated into a more comprehensive procedure, process orfabrication having additional functionality not described in detailherein.

FIG. 1 illustrates a solar cell 100 comprising a silicon substrate 104.The solar cell 100 comprises the silicon substrate 104 and anetch-resistant dopant material 110, 112 deposited on the surface of thesilicon substrate 104. The etch-resistant dopant material 110, 112 canbe dispensed in liquid or semi-liquid form on the silicon substrate 104through various techniques, but is not limited to, comprising thefollowing: screen printing, ink-jet printing and spin coating. Althoughtwo regions of etch-resistant dopant material 110, 112 are shown, moreor fewer can be deposited on the silicon substrate 104 in otherembodiments. The etch-resistant dopant material 110, 112 can be formedin repeated patterns, including masked patterns, on the siliconsubstrate 104.

In certain embodiments, each deposition of etch-resistant dopantmaterial 110, 112 can comprise a solvent, a pre-matrix material, and adopant source 120, 122. Various embodiments of the etch-resistant dopantmaterial 110, 112 can contain all or some selection of these components,as well as other components, as desired. In certain embodiments, theetch-resistant dopant material 110, 112 can have properties similar tothose disclosed in dopant materials described in U.S. patent applicationSer. No. 13/250,215, titled “DOPANT INK COMPOSITION AND METHOD OFFABRICATING A SOLAR CELL THERE FROM”, filed on Sep. 30, 2011.

The dopant source 120, 122 can comprise a single-polarity dopant sourceincluding either a positive-type dopant source or negative-type dopantsource. For example, a positive-type dopant source can include boron ora boron composite, while a negative-type dopant source can includephosphorus or a phosphorus composite.

Although referred to as an etch resistant dopant material, the dopantmaterial containing the dopant source and other components describedabove can in some embodiments have no etch resistance propertiesaccordingly, in some embodiments the dopant material can be used solelyfor doping and not in any etch process. Additionally, when referred toas etch resistant the dopant material need only be resistant to a singletype of etchant. In some embodiments the etch resistant dopant materialcan resist a wide spectrum of etchants. In other embodiments it canresist a few. Moreover the etch resistant dopant material can beresistant to one type of etchant while susceptible to etching by anothertype of etchant. Thus the dopant material or etch resistant dopantmaterial is used interchangeably throughout to refer to dopant materialswhich have the appropriate properties to perform the functions describedthroughout. Therefore although referred to as an etch resistant dopantmaterial it should be understood that the appropriate dopant materialcan be selected for the desired embodiment, depending on whether etchresistance is required or not.

The configuration of etch-resistant dopant material 110, 112 inindependent groups merely suggests one configuration in which the dopantsources 120, 122 are intended to be driven into the silicon substrateand, hence, the arrangement into which the etch-resistant dopantmaterials 110, 112 can be dispensed. In some embodiments it is possiblefor a positive-type dopant source to be found in the location of theetch-resistant dopant material 110 and a negative-type dopant source tobe found in the etch-resistant dopant material 112. The opposite canalso be true, where negative-type dopant source is dispensed in thelocation of the etch-resistant dopant material 110 and a positive-typedopant source is dispensed in the etch-resistant dopant material 112. Inanother embodiment, it is possible for both the etch-resistant dopantmaterials 110, 112 to both contain either only positive-type dopantsources or negative-type dopant sources.

The solar cell 100 formed can be a back contact, back junction (BCBJ)solar cell in any of a number of embodiments, including thoseillustrated and described herein. Although the solar cell 100 can haveany number of the discussed embodiments it is not limited to thestructures described therein.

FIGS. 2-6 further illustrate processing of solar cell 100 in sequentialsteps of the solar cell manufacturing process using printed dopants onsilicon substrates.

FIGS. 2-3 illustrate a non-thermal cure of the etch-resistant dopantmaterial 110, 112 forming a cross-linked matrix 130 on the siliconsubstrate 104.

A non-thermal cure 150 of the etch-resistant dopant material 110, 112can be performed after deposition of the etch-resistant dopant material110, 112. A non-thermal cure 150 can be causing a phase change of theetch-resistant dopant material 110, 112 during the forming of thecross-linked matrix 130 on the silicon substrate 104. In someembodiments, the non-thermal cure 150 of the etch-resistant dopantmaterial 110, 112 forming a cross-linked matrix 130 can compriseexposing the etch-resistant dopant material 110, 112 to non-infraredelectromagnetic radiation. The exposure to the non-infraredelectromagnetic radiation can further comprise exposure of theetch-resistant dopant material 110, 112 to ultraviolet light. In someembodiments, the non-thermal cure 150 can further comprise exposure ofthe etch-resistant dopant material 110, 112 to light in the visiblespectrum. For example, the non-thermal cure 150 can include exposure ofthe etch-resistant dopant material 110, 112 to electromagnetic (EM)radiation having a wavelength between 380 and 760 nanometers, includingsequences of such EM radiation, such as pulses, flashes, or changingintensity. In certain embodiments, the sequences can include repetitionsof the same wavelength of EM radiation, while in others, severaldifferent wavelengths of EM radiation can be used in the same sequence.

In yet another embodiment the non-thermal cure 150 of the etch-resistantdopant material 110, 112 can comprise transmitting acoustic waves towardthe etch-resistant dopant material 110, 112, thereby forming across-linked matrix 130 in the etch-resistant dopant material 110, 112on the silicon substrate 104.

FIG. 3 illustrates the ordered structure of the dopant sources 120, 122is due to the cross-linked matrix 130 within the etch-resistant dopantmaterial 110, 112 formed on the silicon substrate 104. Althoughillustrated as a rectilinear grid, the cross-linked matrix 130 presentin the dopant material 110, 112 can form any arrangement resulting fromthe non-thermal cure step 150 and composition of the dopant material110, 112. Thus, in certain embodiments, crystalline structures can beformed, as an example. Moreover, although the dopant source 120, 122 isillustrated as arranged at vertices within the cross-linked matrix 130,the dopant source 120, 122 can be interstitially arranged, or otherwisepresent in the dopant material 110, 112 without being bonded with orcoupled to or integral of the cross-linked matrix 130. Additionally, thecross-linked matrix 130 need not be a physical arrangement and caninstead be formed of chemical bonding, such as covalent bonding, withinthe dopant material 110, 112, where such bonds are formed as a result ofthe non-thermal cure step 150. Thus, the cross-linked matrix 130 caninclude spirals, helical, or other structural arrangements, includingbonds or linking between such structures.

FIGS. 4-6 illustrates heating 160 the silicon substrate 104 and theetch-resistant dopant material 110, 112 to a temperature sufficient tocause the dopant source to diffuse 140, 142 into the silicon substrate104. Such a diffusion can include interstitial substitution of thedopant source 120 into the silicon lattice. In certain embodiments, thesilicon substrate 104 can then be selectively etched to remove theetch-resistant dopant material 110, 112 without etching the siliconsubstrate 104.

FIG. 4 illustrates the thermal heating 160 of the etch-resistant dopantmaterial 110, 112 on the silicon substrate 104 causing the dopant source120, 122 to diffuse into the silicon substrate 104. The thermal heating160 can comprise of raising the temperature of the etch-resistant dopantmaterial 110, 112 on the silicon substrate 104 to a first temperature ofat least 400° Celsius, at most 1200° C. anywhere therebetween. Incertain embodiments, thermal cycling can be used, raising and loweringthe temperature to any desired temperature for any desired length oftime to accomplish the dopant diffusion. This process may be performedusing specific temperature profiles that are optimized to get the mostuniform diffusion of dopant source 120, 122 into the silicon substrate104. The dopant source 120, 122 can have a concentration in thediffusion regions 140, 142 of at least 1×10¹⁷ atoms per cubiccentimeter. In other embodiments, greater or lower concentrations ofdopant source 120, 122 in the diffusion regions 140, 142 can be present.Any type of doping of the silicon substrate 104 or other target surfacecan be accomplished using this technique, including interstitial orsubstitution diffusion.

FIG. 5 illustrates the diffusion of the dopant sources 120, 122 into thesilicon substrate 104 after performing the thermal heating 160. Thedopant source 120, 122 shown in FIG. 5 may comprise a single-polaritydopant source including either a positive-type dopant source ornegative-type dopant source resulting in the corresponding polarity inthe diffusion regions 140, 142.

FIG. 6 illustrates a subsequent step, wherein the silicon substrate 104is selectively etched to remove the etch-resistant dopant material 110,112 without etching the silicon substrate 104, including the diffusionregions 140, 142. With the etch-resistant dopant material 110, 112removed, the solar cell 100 comprises at least the silicon substrate 104and the diffused regions 140, 142, though earlier processing steps mayhave added other structures, as later processing steps may also.

FIG. 7-9 illustrates an alternative embodiment in which the step ofreducing the volume of solvent in the etch-resistant dopant material110, 112 by heating the etch-resistant dopant material to at least 200°Celsius after forming the cross-linked matrix 130 in the reducedetch-resistant dopant material 170, 172 is performed. As shown in FIG.7, the reduced volume of the etch-resistant dopant material 110, 112 canbe caused by heating the silicon substrate 104, including theetch-resistant dopant material 110, 112. In certain embodiments, thedrive-off of the solvent can be accomplished without altering thestructure of the cross-linked matrix 130. FIGS. 8 and 9 illustrate asubsequent diffusion step, similar to that shown in FIG. 5 above, and adopant material removal step similar to that shown in FIG. 6 above.

FIG. 10 illustrates an embodiment of a solar cell 200 formed with a thindielectric layer 270 atop of the silicon substrate 204. Unless otherwiseindicated, components in FIGS. 10-17 are similar to those describedabove with reference to FIGS. 1-9, except that the numerical indicatorused to designate the component has been incremented by 100. Below thesilicon substrate 204 can be an anti-reflective coating (ARC) 280. Theseand other elements of a solar cell structure can be present on eitherside of the solar cell 200 at various points during fabrication of thesolar cell 200. Accordingly, the formation of diffusion regions canoccur during any appropriate place in the fabrication process. Thus, anetch-resistant dopant material 210, 212 can be deposited on the surfaceof the dielectric layer 270. The etch-resistant dopant material 210, 212can be include a member of a chemical group comprising silanes,cyclosilanes, and siloxanes.

FIG. 11 illustrates exposure of the etch-resistant dopant material 210,212 to ultraviolet light 250. The ultraviolet light 250 cause a phasechange in the etch-resistant dopant material 210, 212, causing theformation of the cross-linked matrix 230 through a photo-polymerizationprocess. In one embodiment the ultraviolet light exposure 250 of theetch-resistant dopant material 210, 212 forming a cross-linked matrix130 can comprise of exposing the etch-resistant dopant material 210, 212to electromagnetic radiation having a wavelength of between 8 and 400nanometers. UV exposure can last for any desired period of time,although a shorter duration of exposure to achieve sufficientcross-linked matrix formation can be beneficial, as compared to arelatively longer duration, for throughput purposes during massproduction. The exposure to the ultraviolet light exposure 250 can causea curing step such as acrylate polymerization, cationic polymerization,thiolene chemical application, and hydrosilane addition.

FIG. 12 illustrates the cross-linked matrix 230 within theetch-resistant dopant material 210, 212 formed on the dielectric layer270.

FIG. 13 illustrates the thermal heating 260 of the etch-resistant dopantmaterial 210, 212, thereby causing the dopant source 220, 222 to diffuseinto the silicon substrate 204.

FIG. 14 illustrates the diffusion of the dopant sources 220, 222 intothe silicon substrate 204 after performing the thermal heating 260resulting in the diffused region 240, 242.

FIG. 15 illustrates an embodiment of the solar cell 204 furthercomprising the step of etching the silicon substrate 204 using theetch-resistant dopant material 210, 212 as an etch-mask after formingthe cross-linked matrix 230 in the etch-resistant dopant material 210,212. The result is an etched away exposed region 290 seen in FIG. 15that may act as a potential barrier between the diffused region 240 andthe diffused region 242. The type of etch performed can be selected toetch the dielectric layer 270. Similarly, the underlying siliconsubstrate 204 can be additionally etched, depending on the selection ofetchant and duration of etch bath. The ARC 280 layer can be etched ornot, as desired for the embodiment.

FIG. 16 illustrates the solar cell 200 as a result of performing aselective etching process to remove the etch-resistant dopant material210, 212 without further etching the silicon substrate 204. With theetch-resistant dopant material removed, the solar cell 200 is comprisedof the diffused region 240 and the diffused region 242 separated by theetched away exposed region within the silicon substrate 204.

FIG. 17 illustrates an embodiment wherein etching the silicon substrate204 using the etch-resistant dopant material 210, 212 as an etch-maskafter forming the cross-linked matrix 230 in the etch-resistant dopantmaterial 210, 212 does not damage the silicon substrate 204, dielectriclayer 270, or any other structure present on the solar cell 200. Such anetching can be used to further process other structural elements of thesolar cell 200 not illustrated for clarity.

FIG. 18 illustrates a solar cell 300 formed with a dielectric layer 370formed on top of the silicon substrate 304. Unless otherwise indicated,components in FIGS. 18-24 are similar to those described above withreference to FIGS. 10-17, except that the numerical indicator used todesignate the component has been incremented by 100. In certainembodiments of the solar cell 300, a polysilicon layer 380 can be formedon top of dielectric layer 370. An etch-resistant dopant material 310,312 can be deposited, such as by ink-jet or other dispensation, asdescribed above with reference to FIG. 1, on the surface of thepolysilicon layer 380. The etch-resistant dopant material 310, 312 caninclude dopant source 320, 322.

With reference to FIGS. 19-20, a non-thermal cure 350 of theetch-resistant dopant material 310, 312 can be performed to formcross-linked matrix 330 on the silicon substrate 304. FIG. 21illustrates the ordered structure of the dopant sources 320, 322 is dueto the cross-linked matrix 330 within the etch-resistant dopant material310, 312 formed on the polysilicon layer 380.

FIGS. 22-24 illustrate the heating 360 of the solar cell 300, includingthe etch-resistant dopant material 310, 312 and the polysilicon layer380 to a temperature sufficient to cause the dopant source to diffuseinto the silicon substrate 304, as described above with reference toFIGS. 1-9. This process may be performed using specific temperatureprofiles that are optimized for uniformity of diffusion of dopant source320, 322 into the polysilicon layer 380, or so as to reach a desiredconcentration of the dopant source 320, 322 in the silicon substrate304, thus forming the diffusion regions. Subsequently, the solar cell300 can be etched to remove the etch-resistant dopant material 310, 312without etching the silicon substrate 304.

FIGS. 25-26 illustrate the step of etching the polysilicon layer 380using the etch-resistant dopant material 310, 314 as an etch-mask afterthermal heating 360 the etch-resistant dopant material 310, 312. Incertain embodiments, the dielectric layer 370 can be similarly etched.The result is an etched away exposed region 390 that acts as a potentialbarrier between the diffused regions 340, 342. The etch-resistant dopantmaterial 310, 312 can be subsequently washed or etched from thepolysilicon layer 380.

FIG. 27 illustrates an alternative embodiment of solar cell 300, whereinthe etch-resistant dopant material 310, 312 may be dispensed in anarrangement of interdigitated contact fingers 400 on the polysiliconlayer 380. In other embodiments, the interdigitated contact fingers 400can be formed directly atop the silicon substrate 304, while in stillothers, the interdigitated contact fingers 400 can be formed atop adielectric layer or other solar cell structure formed on the substrate304.

FIGS. 28 to 31 illustrate an alternative embodiment of the solar cell300, wherein the step of etching the polysilicon layer 380 using theetch-resistant dopant material 310, 312 as an etch-mask is performedfollowing formation of the cross-linked matrix 330. This step can befollowed by the thermal heating 360 of the etch-resistant dopantmaterial 310, 312 to diffuse the dopant source 320, 322 into the,polysilicon layer 380. The polysilicon layer 380 can then be exposed toa selective etchant to remove the etch-resistant dopant material 310,312 without etching the polysilicon layer 380 as seen in FIG. 26. Inanother embodiment, the polysilicon layer 380 can be exposed to anetchant to remove the etch-resistant dopant material 310, 312 while alsoetching the polysilicon layer 380 resulting in an exposed region 390that can form a potential barrier between the diffusion regions 340,342. The etch-resistant dopant material 310, 312 can be subsequentlywashed or etched from the polysilicon layer 380 resulting in the solarcell structure illustrated in the embodiment of FIG. 26.

FIG. 31 illustrates another embodiment of a solar cell. In someembodiments of the solar cell fabrication, etching or washing of theetch-resistant dopant material 310, 312 (including use of an etchantselected for efficacy against the etch-resistant properties of thedopant material 310, 312), the etched-away exposed region 410 may etchthrough the dielectric layer and can reach and etch the siliconsubstrate 304, depending on the etchant and etchant concentration used.Thus, as illustrated in FIG. 31, in some embodiments, the exposed region410 can extend through the dielectric layer 370. In certain embodiments,structural formation can occur in the exposed region 410, forming arandomly-texturized pattern.

The step of etching any of the polysilicon layer 380, dielectric layer370, or silicon substrate 304 during the fabrication process can beperformed at any stage of the overall process after deposition of theetch-resistant dopant material 310, 312. Thus, the material itself canact as an etch mask. In some embodiments, the desired etch-resistantproperties can be present prior to the non-thermal cure step, whereinthe cross-linked matrix is formed. In other embodiments, the dopantmaterial can act as an etch mask after solvent drive-out, after dopantdrive into the dielectric layer, silicon substrate, or a polysiliconlayer, after any number of other process steps, so long as it occursprior to removal of the etch-resistant dopant material. Thus, theetch-resistant dopant material can serve as an mask for etching in anydesired process step, contributing to the formation of any solar cellstructure illustrated herein or manufacturable using the techniquesdescribed.

In some embodiments, however, the etch-resistant dopant material 310,312 need not be used as an etching mask at all. The etch-resistantdopant material can be used solely as a dopant source and thereafterremoved from the solar cell structure without performing a role inetching other features. In some embodiments, the dopant material,etch-resistant or not, can remain on the solar cell and incorporatedinto the emitter or contact structure.

It should be appreciated that the various tasks performed in connectionwith the solar cell manufacturing process can include any number ofadditional or alternative tasks. The tasks shown in FIG. 1-31 need notbe performed in the illustrated order, and additional steps may beincorporated into a more comprehensive procedure or process havingadditional functionality not described in detail herein.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or embodiments described herein are not intended tolimit the scope, applicability, or configuration of the claimed subjectmatter in any way. Rather, the foregoing detailed description willprovide those skilled in the art with a convenient road map forimplementing the described embodiment or embodiments. It should beunderstood that various changes can be made in the function andarrangement of elements without departing from the scope defined by theclaims, which includes known equivalents and foreseeable equivalents atthe time of filing this patent application.

What is claimed is:
 1. A method of manufacturing solar cells, the methodcomprising: forming a thin dielectric layer on a surface of a siliconsubstrate; forming a polysilicon layer over the thin dielectric layer;depositing, in liquid phase, an etch-resistant dopant materialcomprising a dopant source material and a solvent on the polysiliconlayer; forming a cross-linked matrix in the etch-resistant dopantmaterial using a non-thermal cure of the etch-resistant dopant material,the cross-linked matrix having a structure, and the non-thermal curecausing a phase change of the etch-resistant dopant material from liquidto solid; subsequently, removing the solvent from the etch-resistantdopant material without altering the structure of the cross-linkedmatrix; and heating the etch-resistant dopant material to a temperaturewherein the dopant source material diffuses into the polysilicon layer.2. The method of claim 1, further comprising the step of etching thepolysilicon layer using the etch-resistant dopant material as anetchmask.
 3. The method of claim 1, wherein depositing theetch-resistant dopant material comprises dispensing the etch-resistantdopant material in a plurality of interdigitated contact fingers on thesilicon substrate.
 4. A method of manufacturing solar cells, the methodcomprising: depositing, in a liquid phase, an etch-resistant dopantmaterial on a polysilicon layer disposed on a thin dielectric layerdisposed on a silicon substrate, the etch-resistant dopant materialcomprising a dopant source and a solvent; forming a cross-linked matrixin the etch-resistant dopant material using a non-thermal cure of theetch-resistant dopant material, the cross-linked matrix having astructure, and the non-thermal cure causing a phase change of theetch-resistant dopant material from liquid to solid; subsequently,removing the solvent from the etch-resistant dopant material withoutaltering the structure of the cross-linked matrix; and heating thepolysilicon layer and the etch-resistant dopant material having thecross-linked matrix to a temperature sufficient to cause the dopantsource to diffuse into the polysilicon layer.
 5. The method of claim 4,wherein forming the cross-linked matrix in the etch-resistant dopantmaterial using the non-thermal cure of the etch-resistant dopantmaterial comprises exposing the etch-resistant dopant material tonon-infrared electromagnetic radiation.
 6. The method of claim 5,wherein exposing the etch-resistant dopant material to the non-infraredelectromagnetic radiation comprises exposing the etch-resistant dopantmaterial to ultraviolet light.
 7. The method of claim 5, whereinexposing the etch-resistant dopant material to the non-infraredelectromagnetic radiation comprises exposing the etch-resistant dopantmaterial with light from the visible spectrum or electromagneticradiation having a wavelength of 380 to 760 nanometers.
 8. The method ofclaim 4, wherein forming the cross-linked matrix in the etch-resistantdopant material using the non-thermal cure of the etch-resistant dopantmaterial comprises transmitting acoustic waves toward the etch-resistantdopant material.
 9. The method of claim 4, wherein depositing theetch-resistant dopant material comprises dispensing the etch-resistantdopant on the polysilicon layer.
 10. The method of claim 9, whereindispensing the etch-resistant dopant material comprises screen printingthe etch-resistant dopant material onto the polysilicon layer.
 11. Themethod of claim 9, wherein dispensing the etch-resistant dopant materialcomprises ink-jet printing the etch-resistant dopant material onto thepolysilicon layer.
 12. The method of claim 9, wherein dispensing theetch-resistant dopant material comprises spin coating the etch-resistantdopant material onto the polysilicon layer.
 13. The method of claim 9,wherein dispensing the etch-resistant dopant material comprising thedopant source onto the polysilicon layer comprises dispensing a dopantmaterial comprising a single-polarity dopant source onto the polysiliconlayer.
 14. The method of claim 13, wherein dispensing the dopantmaterial comprising the single-polarity dopant source onto thepolysilicon layer comprises dispensing a positive-type dopant onto thepolysilicon layer.
 15. The method of claim 13, wherein dispensing thedopant material comprising the single-polarity dopant source onto thepolysilicon layer comprises dispensing a negative-type dopant onto thepolysilicon layer.
 16. The method of claim 4, wherein removing thesolvent from the etch-resistant dopant material comprises heating theetch-resistant dopant material to at least 400° Celsius.
 17. A method ofmanufacturing solar cells, the method comprising: depositing, in aliquid phase, a dopant material on a polysilicon layer disposed on athin dielectric layer disposed on a silicon substrate having aphotovoltaic solar cell structure, the dopant material comprising adopant and a solvent; forming a cross-linked matrix in the dopantmaterial using a non-thermal exposure of the dopant material toultraviolet light through a photo-polymerization process, thecross-linked matrix having a structure, and the photo-polymerizationprocess causing a phase change of the dopant material from liquid tosolid; subsequently, removing the solvent from the dopant materialwithout altering the structure of the cross-linked matrix; and heatingthe polysilicon layer and the dopant material having the cross-linkedmatrix to a temperature sufficient to cause the dopant to diffuse intothe polysilicon layer.
 18. The method of claim 17, wherein forming thecross-linked matrix in the dopant material using the non-thermalexposure of the dopant material to the ultraviolet light comprisesexposing the dopant material to electromagnetic radiation having awavelength of 8 to 400 nanometers.
 19. The method of claim 17, whereindepositing the dopant material comprises depositing a chemical groupcomprising a chemical structure selected from the group comprisingsilanes, cyclosilanes, and siloxanes.